1. Field of the Invention
This invention relates to an environment recognizing device and an environment recognizing method adapted to extract a plane from three-dimensional data including parallax image data and distance image data in an environment where obstacles exist and recognize the obstacles on the extracted plane, to a route planning device and a route planning method adapted to plan a moving route from the current position to a target position on the basis of an environment map obtained by the environment recognition and also to a robot quipped with such an environment recognizing device or a route planning device.
This application claims priority of Japanese Patent Application No. 2003-329129, filed on Sep. 19, 2003, the entirety of which is incorporated by reference herein.
2. Description of Related Art
A “robot” is a machine that is electrically or magnetically driven to do movements that resemble human (living body) actions. In Japan, robots became popular in the late 1960s but many of them were industrial robots including manipulators and transfer robots that were designed to realize automated and unattended production lines in factories.
Recently, efforts have been and being paid to develop utility robots that support people as partners, behaving like men, in various scenes of our daily lives in living environments. Unlike an industrial robot, a utility robot has the ability of learning how to adapt itself to various people having different personalities and various circumstances in different scenes of our daily lives in living environments. For example, “pet type” robots that resemble four-footed animals such as dogs and cats in terms of bodily mechanisms and movements and “human type” or “human-shaped” robots that are designed by using men or some other two-footed animals as model in terms of bodily mechanisms and movements are already being in the stage of practical use.
If compared with industrial robots, utility robots can act to entertain people so that they are sometimes also referred to as entertainment robots. Additionally, some robots of the type under consideration can recognize external circumstances on the basis of the outputs of the external sensors and autonomously behave in response to external information and internal conditions.
Meanwhile, it may be needless to say that it is important for an autonomous robot to have an ability to recognize the environment surrounding it, plan a moving route and move according to the planned moving route. For a robot to recognize the environment, it is necessary to obtain information on the obstacles in the surroundings of the robot. Therefore, the robot needs to detect a plane, which may be a floor, from three-dimensional data including parallax image data and distance image data and recognize the obstacles.
Japanese Patent Application Publication No. 3340599 discloses a plane estimation method that utilizes Hough transformation in order to detect a plane from three-dimensional data for the purpose of accurately obtain distance data on a plane. With the technique described in the above cited patent document, a plane is estimated in a picked up spatial image by dividing a stereo image into small rectangular regions, obtaining distance data from each of the small regions, applying a plane-passing line by means of Hough transformation from the M distance data contained in each large region formed by putting small regions into a group in a horizontal direction and conducting the same operation for all the large regions.
However, as a traveling type robot detects a plane as a floor in this way, a moving route plan is prepared so as to avoid objects on the floor as obstacles. Then, when an autonomously moving robot is designed to detect an object standing from the floor as obstacle, there arises a problem that a staircase on which the robot actually can move is detected as an obstacle so that the robot may judge that it can not move there. For a robot that can step up a staircase may recognize it as an obstacle unless information including the position and profile of the staircase and the fact that the robot can move on it is given to the robot in advance.